/******************************************************************
 *
 * Copyright 2018 Samsung Electronics All Rights Reserved.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 ******************************************************************/

/****************************************************************************
 *
 *   Copyright (C) 2016 Gregory Nutt. All rights reserved.
 *   Author: Gregory Nutt <gnutt@nuttx.org>
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 * 3. Neither the name NuttX nor the names of its contributors may be
 *    used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 *
 ****************************************************************************/

/****************************************************************************
 * Included Files
 ****************************************************************************/

#include <tinyara/config.h>

#include <stdint.h>
#include <tinyara/irq.h>
#include <tinyara/arch.h>
#include <assert.h>

#include <tinyara/board.h>
#include <arch/board/board.h>
#include <arch/chip/core-isa.h>

#include "xtensa.h"

#include "group/group.h"
#include "sched/sched.h"

/****************************************************************************
 * Public Functions
 ****************************************************************************/

uint32_t *xtensa_irq_dispatch(int irq, uint32_t *regs)
{

#ifdef CONFIG_SUPPRESS_INTERRUPTS
	board_autoled_on(LED_INIRQ);
	PANIC();

#else
#if XCHAL_CP_NUM > 0
	/* Save the TCB of in case we need to save co-processor state */

	struct tcb_s *tcb = this_task();
#endif

	board_autoled_on(LED_INIRQ);

	/* Nested interrupts are not supported */

	DEBUGASSERT(CURRENT_REGS == NULL);

	/* Current regs non-zero indicates that we are processing an interrupt;
	 * CURRENT_REGS is also used to manage interrupt level context switches.
	 */

	CURRENT_REGS = regs;

	/* Deliver the IRQ
	 *
	 * NOTE: Co-process state has not been saved yet (see below).  As a
	 * consequence, no interrupt level logic may perform co-processor
	 * operations.  This includes use of the FPU.
	 */

	irq_dispatch(irq, regs);

#if XCHAL_CP_NUM > 0 || defined(CONFIG_ARCH_ADDRENV)
	/* Check for a context switch.  If a context switch occurred, then
	 * CURRENT_REGS will have a different value than it did on entry.
	 */

	if (regs != CURRENT_REGS) {
#if XCHAL_CP_NUM > 0
		/* If an interrupt level context switch has occurred, then save the
		 * co-processor state in in the suspended thread's co-processor save
		 * area.
		 *
		 * NOTE 1. The state of the co-processor has not been altered and
		 *         still represents the to-be-suspended thread.
		 * NOTE 2. We saved a reference  TCB of the original thread on entry.
		 */

		xtensa_coproc_savestate(&tcb->xcp.cpstate);

		/* Then set up the co-processor state for the to-be-started thread.
		 *
		 * NOTE: The current thread for this CPU is the to-be-started
		 * thread.
		 */

		tcb = this_task();
		xtensa_coproc_restorestate(&tcb->xcp.cpstate);
#endif

#ifdef CONFIG_ARCH_ADDRENV
		/* Make sure that the address environment for the previously
		 * running task is closed down gracefully (data caches dump,
		 * MMU flushed) and set up the address environment for the new
		 * thread at the head of the ready-to-run list.
		 */

		(void)group_addrenv(NULL);
#endif
	}
#endif

	/* Set CURRENT_REGS to NULL to indicate that we are no longer in an
	 * interrupt handler.
	 */

	regs = (uint32_t *)CURRENT_REGS;
	CURRENT_REGS = NULL;
#endif

	board_autoled_off(LED_INIRQ);
	return regs;
}
